1. Field of the Invention
The present invention relates to a magnetoresistive effect device including a magnetoresistive effect element.
2. Description of the Related Art
The speed of wireless communication has increased in recent years with the increasing functions of mobile communication terminals, such as mobile phones. Since the communication speed is proportional to the band width of frequencies that are used, the number of frequency bands necessary for communication is increased. Accordingly, the number of high-frequency filters that are mounted in mobile communication terminals is increased. Spintronics has been studied in recent years as a field that is probably applicable to new high-frequency components. One phenomenon that has received attention is the spin torque resonance phenomenon, which is caused by a magnetoresistive effect element (refer to Nature, Vol. 438, No. 7066, pp. 339 to 342 17 Nov. 2005). Application of an alternating current to a magnetoresistive effect element causes spin torque resonance in the magnetoresistive effect element, and the resistance value of the magnetoresistive effect element oscillates with a fixed cycle at a frequency corresponding to a spin torque resonance frequency. The spin torque resonance frequency of the magnetoresistive effect element varies with the strength of the magnetic field applied to the magnetoresistive effect element. The spin torque resonance frequency of the magnetoresistive effect element is generally within a high-frequency band from several gigahertz to several tens of gigahertz.